Gardaí have issued a fresh appeal to members of the public and taxi drivers who were in the Coolock area on the night of the Donna Cleary murder.
They have asked taxi drivers to contact them if they accepted any fares or dropped anyone off at Coolock's Adare Green between 1.30am and 2.45am on Sunday morning.
They are also seeking information on silver car with a number of passengers that was seen in the area around the same time.
A sixth person is still being questioned about the murder the mother of one.
Ms Cleary (22) died after gunmen fired shots into a house in Coolock in north Dublin early last Sunday morning.
A Garda spokesman said a man (21) presented himself at Coolock Garda Station last night and was detained under Section 30 of the Offences against the State Act.
He is being questioned over the illegal possession of a firearm and had been sought by detectives investigating the shooting at a 40th birthday party near the victim's home.
Five others who were arrested in connection with the murder earlier this week were later released without charge.